Proteins and polypeptides have become increasingly important as therapeutic agents. In most cases, therapeutic proteins and polypeptides are produced in cell culture, from cells that have been engineered and/or selected to produce unusually high levels of the particular protein or polypeptide of interest. Control and optimization of cell culture conditions is critically important for successful commercial production of proteins and polypeptides.
Many proteins and polypeptides produced in cell culture are made in a batch or fed-batch process, in which cells are cultured for a period of time, and then the culture is terminated and the produced protein or polypeptide is isolated. The ultimate amount and quality of protein or polypeptide produced can be dramatically affected by the conditions of the cell culture. For example, traditional batch and fed-batch culture processes often result in production of metabolic waste products that have detrimental effects on cell growth, viability, and production or stability of the protein or polypeptide of interest. While efforts have been made to improve production of proteins and polypeptides in batch and fed-batch culture processes, there remains a need for additional improvements.
Additionally, significant effort has been invested in the development of defined media (i.e., media assembled from known individual components and lacking serum or other animal byproducts) for use in culturing cells, particularly mammalian cells. Cell growth characteristics can be very different in defined media as contrasted with serum-derived media. There is a particular need for the development of improved systems for producing proteins and polypeptides by cell culture in defined media.